In the constructional design of lighting devices using, as a light radiation source, linear modules or arrays, for example of the LED types, it is possible to use optical systems (lenses or mirrors, singly or in an array) which produce at the output of the device a fixed light beam.
In order to modify the features of the radiation beam emitted the optical component must be changed, which may take time and not always be possible, thereby making it necessary to replace the entire module.
In various solutions it is possible to move away from or towards the light radiation source an optical component such as a lens. This allows one to obtain light beams only of circular shape, unless more complex systems are used.